70 results

Using information for 'data-rich' species to inform assessments of 'data-poor' species through Bayesian stock assessment methods

Project number: 2002-094
Project Status:
Completed
Budget expenditure: $176,237.00
Principal Investigator: David Smith
Organisation: Agriculture Victoria
Project start/end date: 29 Sep 2002 - 30 Nov 2005
:
TAGS
Wild Catch
Stock Assessment
Mortality
Modelling
Data

Need

Over 300 species are caught in the SEF, of which around 100 have commercial value. Twenty five species comprise around 90% of the landed catch. Each year, however, quotas are set for only around 17 species. There are 10 of these species for which there is (or has been) some formal stock assessment (that may not occur every year). For all of the remaining quota species and some of the more important non-quota species, no formal assessment is undertaken and the only assessment that can be made is based on investigation of trends in catch and effort and size distribution and anecdotal input from scientists and industry. There is simply not enough resources to undertake formal stock assessments for the wide range of commercial species landed in the SEF. Yet, each of these species is an important component of the catch of fishers. If the fishery is to continue to operate in its current form and meet the strategic assessments required under the EPBC Act, some form of formal assessment is required.

A recently completed ARF project (Production parameters from the fisheries literature for SEF-like species - Project no R99/0308) demonstrated the utility of using information for "similar" species when conducting assessments for SEF species. Using key parameters such as the virgin biomass, the rate of natural mortality, and the “steepness” of the stock-relationship relationship, a simple formula was developed for identifying “similar” stocks / species and an algorithm was developed for constructing prior probability distributions for these parameters. The resultant distributions can be used in Bayesian stock assessments and as the basis for sensitivity tests when applying other methods of stock assessments. The current project will refine the prior distributions for the production parameters and develop and test methods of stock assessment that use the results of assessments for well-studied species in a formal manner to inform assessments of ‘data-poor’ species. If successful, the methods developed would lead to significant benefits not only for the assessment and management of "data poor" SEF low priority, by-product and by-catch species, but also for a range of new and developing fisheries in Australia.

Objectives

1. Expand the database of production parameters for SEF-like species
2. Develop prior probability distributions for steepness and the coefficient of variation about the stock-recruitment relationship using Bayesian meta-analysis
3. Develop a Bayesian framework within which the results for data-rich species can 'inform' assessments for data-poor species.
4. Apply the framework to three case-studies to determine the robustness of the framework.
5. Test the framework by means on Monte Carlo simulation

Final report

ISBN: 1-74146-524-9
Author: David Smith
Final Report • 2009-04-23 • 5.99 MB
2002-094-DLD.pdf
Environment

Viral endemiology of selected Australian commercial fish species and their susceptibility to viral diseases

Project number: 1984-083
Project Status:
Completed
Budget expenditure: $0.00
Organisation: Agriculture Victoria
Project start/end date: 27 Jun 1987 - 29 Jun 1987
:
TAGS
Diagnostic

Objectives

1. Expand the Australian viral endemiology testing facility to include certified continuous cell lines derived from commercially important Australian fish species,
2. enabling the viral endemiology and susceptibility of these fish to be studied
Environment
PROJECT NUMBER • 1998-146
PROJECT STATUS:
COMPLETED

Evaluation of recreational fishery management controls of commercially important scalefish species

There are increasing demands for Australian fisheries management agencies to demonstrate that fisheries under their jurisdiction are being managed in accordance with the principles of ecologically sustainable development (ESD). The decision-making processes of the ESD management framework...
ORGANISATION:
Agriculture Victoria
TAGS
Resource Access And Allocation
SPECIES
Black Bream
Environment
PROJECT NUMBER • 1996-116
PROJECT STATUS:
COMPLETED

Spawning and larval recruitment processes of commercially important species in coastal waters off Victoria

Information on spawning and larval recruitment processes of commercially important species in coastal waters in south-eastern Australian waters is provided based on four daytime surveys carried out on board the RV Franklin during the summer of 1997 (January-February and December) and the winter of...
ORGANISATION:
Agriculture Victoria
TAGS
Survey
Environment
PROJECT NUMBER • 1994-164
PROJECT STATUS:
COMPLETED

Mapping and distribution of Sabella spallanzanii in Port Phillip Bay

This final report for the FRDC funded project "Mapping and distribution of Sabella spallanzanii in Port Phillip Bay" is considered in two sections: The first section contains original data.' collected during this project to satisfy Objectives 1, 2 and 3 and is organised to be suitable for...
ORGANISATION:
Agriculture Victoria
TAGS
Survey

Assessment of the importance of different near-shore marine habitats to important fishery species in Victoria using standardised survey methods, and in temperate and sub-tropical Australia using stable isotope analysis

Project number: 2001-036
Project Status:
Completed
Budget expenditure: $553,689.00
Principal Investigator: Gregory Jenkins
Organisation: Agriculture Victoria
Project start/end date: 7 Nov 2001 - 15 Aug 2005
:
TAGS
Survey
Reproduction
Habitat
Food Web
Distribution

Objectives

1. To increase our understanding of fisheries/habitat links using a combination of standardised survey methods in Victoria and Queensland, and isotope analyses across southern Australia and Queensland.
2. To identify the importance of different near shore habitats for important fish species from recruitment to older-life stages, for individual habitats at broad scales and habitat mosaics at finer scales.
3. To improve the quality of data derived from isotope analyses by including a greater range of potential sources of primary production.
4. To understand the transfer of primary production from important habitats to food chains of fish that occur outside that habitat, and also the sources of primary production for fish inhabiting habitat mosaics.
5. To integrate existing near shore habitat data-sets with detailed descriptions of fish/habitat associations in a spatial information system (GIS) that can be accessed by a variety of user groups.

Final report

ISBN: 1-74146-474-9
Author: Gregory Jenkins
Final Report • 2005-11-01 • 2.67 MB
2001-036-DLD.pdf

Summary

The first part of this project was a basic survey of fish use of intertidal habitats such as mangroves, mudflats and saltmarshes, which previously had hardly been considered in temperate Australian coastal waters.

Mangroves (Avicennia marina) and mudflats were used by at least 41 species of fish. Juvenile stages of 41% of the species were sampled and economic species were common. Mangrove habitat in temperate Australian waters supports a richer juvenile fish assemblage than adjacent mudflats, but there is little difference between habitats for the subadult/adult assemblage. Ultimately, the ‘value’ of mangrove habitats to fishes depends strongly on the time and place.

Saltmarshes were difficult to sample because of unpredictable amounts of water cover. Saltmarsh flats were generally only covered with water during low-pressure weather systems. Most fish caught in this habitat were not of commercial value. Water temperature, salinity, depth or barometric pressure did not explain variability in the number of fish species present or fish abundance. Fish species in the saltmarsh flats also live in other habitats such as seagrass, and the observed patterns of habitat use seemed to partly relate to feeding behaviour.

The second part of the fish-habitat survey work aimed to see how the use of habitats by fish changed within different parts of the habitat, and also with respect to the location of other habitats.

Results from the study will be valuable in the future detection of environmental perturbations, providing a baseline data set against which disturbance effects can be assessed. Information on habitat use, and how multiple habitats interact with each other, will put managers in a stronger position to argue for the preservation of important nursery habitat. Results from this project may also be important in advising on the appropriateness of marine park designs to ensure, among other things, fisheries sustainability.

Keywords: Mangrove, mudflat, saltmarshes, fish, zonation, landscape, seagrass, stable isotope, base for nutritional support, carbon and sulphur stable isotopes, commercial

Environment
Environment

Spawning and reproductive biology of blue grenadier in south-eastern Australia and the winter spawning aggregation off western Tasmania

Project number: 2000-102
Project Status:
Completed
Budget expenditure: $81,623.00
Principal Investigator: David Smith
Organisation: Agriculture Victoria
Project start/end date: 16 Oct 2000 - 30 Jul 2008
:
TAGS
Threatened Endangered Protected Species
Reproduction
Modelling
Biomass
Aquaculture

Need

By mass, the catch of blue grenadier is currently the largest of all of the quota species in the South East Fishery. Blue grenadier is also currently the second most valuable species in the South East Fishery (8.8M during 1998). Industry reports that it anticipates the 10,000t TAC will be taken during 1999 due to the continuing development of the spawning fishery following the introduction of 'factory trawlers' in recent years.

Current assessment of the fishery is undertaken by the The Blue Grenadier Assessment Group (BGAG) which was formed in 1997. BGAG comprises government and industry scientists, industry representatives and AFMA managers. The 1999 assessment of blue grenadier uses an age-structured ‘synthesis’ model (Punt et al in press). The assessment considers fishing during the spawning season off Western Tasmania and that at other times/places separately. The model uses catch (including discards), standardised catch rates and catch-at-age data (retained and discards) as well as estimates of absolute abundance based on the egg production method. The results of the current assessment are generally optimistic for the next five to ten years but are extremely sensitive to biomass estimates from the egg production method.

One key area of uncertainty concerns the proportion of mature fish that spawn each year. It is known from data in New Zealand that not all fish spawn annually. Assessments in New Zealand are based on the assumption that 77% (the average of the range of 68-85% reported by Livingston et al., 1997) of the potential spawners spawn each year. The same assumption is used by BGAG. However, there are no data on the proportion of non-spawners in Australia although there are anecdotal reports of adult fish (non-spawners?) outside spawning areas during the main spawning season. It is important, therefore, that we establish the actual proportion of non-spawning fish as this can have a significant impact on the mature biomass.

Obtaining better information on the spawning behaviour and reproductive biology of blue grenadier to reduce uncertainty about biomass estimates has been accorded a high priority for several years and was stressed again by BGAG in 1999. Information needed includes fecundity estimates, maturity ogives and the proportion of non-spawners.

Objectives

1. Estimate the annual proportion of non-spawning adults in the blue grenadier stock off south-eastern Australia
2. Describe macroscopic and histological maturation stages and gonad cycles
3. Accurately determine the size at maturity and the proportion of each age class developing to spawn
4. Evaluate levels of spawning of blue grenadier in areas outside the main spawning aggregation.

Final report

ISBN: 978-1-74217-642-0
Final Report • 2009-08-19 • 1.48 MB
2000-102-DLD.pdf
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